Search

Guide to LV/MV/HV switchgears and substations

This guide covers three subchapters: High voltage substations, Medium voltage substations and Low voltage substations. When selecting a low voltage main distribution system, the…
Guide to LV/MV/HV switchgears and substations
Guide to LV/MV/HV switchgears and substations (photo credit: warrencat.com)

Introduction

This guide covers three subchapters:

  1. High voltage substations,
  2. Medium voltage substations and
  3. Low voltage substations.

Low voltage main distribution

When selecting a low voltage main distribution system, the prerequisite for its efficient sizing is knowing about its use, availability and future options for extension. The requirements for power distribution are extremely diverse.

Normally, frequent switching operations need not be considered in the planning of power distribution for commercial, institutional and industrial building projects, and extensions are generally not to be expected. For these reasons, a performance-optimized technology with high component density can be used.

Low voltage distribution switchgear max. 7 000 A - SIVACON S8
Low voltage distribution switchgear max. 7 000 A – SIVACON S8

In these cases, Siemens mainly uses circuit breaker protected equipment in fixed-mounted design.

When planning a power distribution system for a production plant, however, system availability, extendibility, control and the visualization of status information and control functions are important issues related to keeping plant downtimes as short as possible.

The use of circuit-breaker protected technology in withdrawable design is important. Selectivity is also of great importance for reliable power supply. Between these two extremes there is a great design variety that should be optimally matched to customer requirements.

The prevention of personal injury and damage to equipment must however, be the first priority in any case. When selecting appropriate switchgear, it must be ensured that it is a design verified switchgear assembly (in compliance with AC 61439-2, VDE 0660-600-2), with extended testing of behavior in the event of an internal arc fault (IEC 61641, VDE 0660-500, Addendum 2).

Low voltage main distribution systems should be chosen among those featuring a total supply power up to 3 MVA.

Low voltage switchgear example
Low voltage switchgear example (SIVACON S8, busbar position at rear HxWxD: 2200x4800x600 mm)

Up to this rating, the equipment and distribution systems are relatively inexpensive due to the maximum short-circuit currents to be encountered.

For rated currents up to 3200A, power distribution via busbars is usually sufficient if the arrangement of the incoming, outgoing feeder panels and coupler panels has been selected in a performance-related way. Ambient air temperatures, load on individual feeders and the maximum power loss per panel have a decisive impact on the devices to be integrated and the number of panels required, as well as their component density (number of devices per panel).


Arc resistance

Arcing faults can be caused by incorrect dimensioning and reductions in insulation due to contamination etc., but they can also be a result of handling errors.

The effects, resulting from high pressure and extremely high temperatures, can have fatal consequences for the operator, the system and even the building. SIVACON offers effidence of personal safety through testing under arcing fault conditions with a special test in accor-dance with IEC 61641 (DIN VDE 0660-500 Addendum 21.

Active protection measures such as the high-quality insulation of live parts (e.g. busbars), standardized and simple operation, prevent arcing faults and the associated personal injuries.

Passive protections increase personal and system safety many times over. These include: hinge and locking systems with arc resistance, the safe operation of withdrawable units or circuit breakers behind a closed door and patented swing check valves behind venitlation openings on the front, arcing fault barriers or arcing fault detection system combined with the rapid disconnection of arcing faults.

Title:Switchgears and Substations Guide – SIEMENS (3rd chapter of Power Engineering Guide, Edition 7.1)
Format:PDF
Size:6.8 MB
Pages:78
Download:Right here | Get Download Updates | Get Technical articles
SIEMENS - Switchgears and Substations Guide
SIEMENS – Switchgears and Substations Guide

SEARCH: Articles, software & guides //

Premium Membership //

Premium membership gives you an access to specialized technical articles and extra premium content (electrical guides and software).
Get Premium Now ⚡

Page edited by E.C. (Google).

4 Comments


  1. sunday adoga
    Sep 17, 2015

    more information on bus riser, bus coupler and bus tie


  2. ashok sonawane
    Mar 05, 2015

    its good but i need constuction and working..


  3. said homeili
    Mar 05, 2015

    Hi dear manager
    I like to understand about microgride and operation in uncertainty aspects. Reliability of microgride in esthetics operation and planning.
    If you can help me .Please send me useful book .articles and book.or useful links.

    Thanks a lot
    said homeili


  4. Anil suneja
    Dec 22, 2013

    this is very simple question and not the standard of engineer

Leave a Comment

Tell us what you're thinking... we care about your opinion!